Electrospun porous polyacrylonitrile nanofibrous membrane grafted with branched polyethyleneimine for efficient adsorption of Cu2+ and Pb2+ from polluted water

Water pollution has emerged as a global environmental concern, primarily due to the harmful effects of heavy metal ions in wastewater. efficient membranous adsorbents are anticipated to remove these pollutants from water. Herein, a branched polyethylenimine (b-PEI) grafted electrospun porous PAN (b-PEI-EPPAN) nanofibrous membranes were facilely fabricated by an integrated strategy of electrospinning technique, pore-forming process, hydrolysis reaction and chemical grafting for efficient removal of Cu2+ or Pb2+ from wastewater. The adsorption performance and mechanism of the membrane were investigated. The results revealed that b-PEI-EPPAN nanofibrous membranes demonstrated rapid adsorption process and superior adsorption capacity for Cu2+ or Pb2+ (maximum adsorption capacities of Cu2+ and Pb2+ were up to 144.10 mg center dot g(-1) and 397.88 mg center dot g(-1)). And could still maintain above 95 % of the initial values of its adsorption capacity at the sixth cycle of adsorptiondesorption. A possible adsorption mechanism could be attributed to surface complexation between Cu2+ or Pb2+ and N-containing functional groups (-NH2 and -NH-). Also, several O-containing functional groups (-CONH-/-CONH2 and -COOH) were favorable for Cu2+ or Pb2+ adsorption. Interestingly, it was observed that the hexagonal flake-like crystals of basic lead carbonate (Pb-3(CO3)(2)(OH)(2)) and the irregular flake-like crystals of copper hydroxide hydrate (Cu(OH)(2)H2O) were grown on b-PEI-EPPAN nanofibrous membrane after adsorption. The ability of the b-PEI-EPPAN membrane to promote the growth of metal crystals after adsorption not only aids in the removal of heavy metals from wastewater but also opens up possibilities for the recovery of these metals, adding to the sustainability and economic viability of wastewater treatment processes.